Australian states have instructed police to issue fines of up to A$11,000 ($6,672) to people who violate federal orders that ban non-essential travel and limit groups of people gathering outside to two.

In New South Wales, the most populous state with nearly a third of the country's 25 million population, police have also threatened prison terms of up to six months for people who violate the rules.

"When is the turn-off period for these orders? It is 90 days," state police commissioner Mick Fuller told a televised news conference in Sydney.

"People will have gotten the message by then, hopefully. And we won't be talking about the powers, we'll be talking about what does it look like coming out of this?"

Police in NSW and other states have already started issuing tickets to people suspected of breaching orders which authorities themselves have called "draconian".

Officials in the second most populous state of Victoria said policing of social distancing rules may last until June, without giving specific dates.

Shutdown bites 

Like countries around the world, Australia has ordered the shutdown of restaurants, cafes, bars, movie theatres and instructed people to stay inside unless they are shopping for food or taking their daily exercise as it tries to contain the flu-like illness. So far, more than 5,200 people have been infected in Australia, and 23 have died.

The restrictions have crippled the local economy, putting hundreds of thousands out of work and hammering investors.

The Australian share market was down about 3% on Thursday, following declines on Wall Street where US health officials gave projections of hundreds of thousands of deaths, quashing hopes of a quick return to business as usual.

Australian health authorities have said infection rates appear to have slowed in recent days but it is too early to say definitively.

The country has meanwhile banned cruise ships from docking after being found to be the biggest single source of coronavirus infections, with 20% of cases linked to passengers and crew from the ships.

Cruise ship arrivals became a source of public anger after hundreds of passengers from Carnival Corp's Ruby Princess were allowed to disembark in Sydney last month and hundreds later tested positive for COVID-19.

A military-style operation was planned to airlift doctors onto eight cruise ships floating off the NSW coast which were refusing orders to leave Australian waters, so that the doctors could conduct health checks on nearly 9,000 crew members, local media reported.

In Western Australia, a standoff continued between immigration officials and foreign-owned cruise ships which were also refusing to leave.

The Maritime Union of Australia said there were 11 foreign-owned cruise ships in limbo in Australian waters, with 11,000 crew members in total, and their situation was "an emerging humanitarian crisis"